Wildlife and Animal Groups

Wildlife refers to undomesticated animals living in their natural environments, and the term covers an enormous range of life. Biologists sort animals into major groups based on shared features. Mammals are hair-bearing, warm-blooded animals that nurse their young with milk, and they include subgroups such as rodents, carnivores, primates, hooved animals, marsupials, and the large land mammals like elephants and rhinoceros. Birds are feathered egg-layers, while reptiles such as turtles, crocodiles, lizards and snakes are scaled, cold-blooded animals, and amphibians like frogs and salamanders typically begin life in water.

Beyond these vertebrate classes lie the invertebrates, animals without a backbone, which make up the overwhelming majority of animal species. Arthropods — insects, spiders, crustaceans and their relatives — are the largest group, characterised by jointed legs and an external skeleton. Fish, the most diverse vertebrate group, dominate aquatic environments. Together these groups form complex food webs in which herbivores, predators and scavengers depend on one another and on their habitats.

Wildlife is distributed across distinct regions and ecosystems. The savannas of Africa, often associated with safari, support large herds of grazing mammals and the predators that hunt them, while rainforests, deserts, wetlands and oceans each host specialised communities. Zoos and nature reserves allow people to observe animals at close range and support research and conservation. Studying wildlife combines ecology, animal behaviour and taxonomy, and increasingly focuses on protecting species and habitats threatened by human activity.

Frequently asked questions

What are the main groups of animals?

The major vertebrate groups are mammals, birds, reptiles, amphibians and fish. Invertebrates, especially arthropods, make up most of the remaining animal species.

What defines a mammal?

Mammals are warm-blooded animals with hair or fur that feed their young with milk produced by mammary glands.

What is wildlife?

Wildlife is the collective term for wild, non-domesticated animals living in their natural habitats rather than under human care.